Method of reproducing a still picture from a recording medium, method of decoding the still picture and the recording medium

ABSTRACT

In the method, video data is reproduced from the recording medium, and an I-picture and a number of P-pictures are output as a still picture based on the reproduced video data. The output data may then be received and decoded for display.

PRIORITY INFORMATION

This is a continuation of application Ser. No. 13/523,320 filed on Jun.14, 2012, which is a continuation of application Ser. No. 12/457,137filed on Jun. 2, 2009, which is a continuation of application Ser. No.10/810,720 filed Mar. 29, 2004, which is a continuation of applicationSer. No. 09/698,623 filed Oct. 30, 2000, which claims priority on KoreanApplication No. 99-217843 filed Oct. 30, 1999; the contents of all ofwhich are hereby incorporated by reference in their entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to method of reproducing data; and moreparticularly, a still picture.

2. Description of the Related Art

A high-density digital versatile disk (HD-DVD), whose recording standardis under discussion among related companies, is a high-capacity storagedevice for moving pictures of large size, so that it will be widely usedsoon. In the meantime, a disk reproducing device (referred as ‘HDVDplayer’ hereinafter) which is being developed to reproduce ahigh-density digital versatile disk is expected to be connected with adigital television through IEEE 1394 standard when it playbacks aninserted disk.

When a HDVD player is connected with a digital television to playback aHD-DVD, it should have specific video pictures to be displayed as stillimages on a screen of a digital television. Examples of the specificvideo pictures are a background image of menu bars for selection ofvarious functions provided from a HD-DVD, and a menu screen for editinga content scenario of a moving picture program recorded in a HD-DVD.

To embody still picture of data stream recorded in a DVD-ROM which isbeing popularized more and more, a still mark is written behind a datastream section corresponding to a still picture, and a DVD-ROM player,which can reproduce a DVD-ROM disk, repeats to output the last-decodedstream section if a still mark is detected while reproducing recordedprograms.

This method is possible since a DVD-ROM player has been developed inexpectation that it is to be connected with an analog television notequipped with a MPEG decoder so that it has a MPEG decoder as aninternal component, therefore, a DVD-ROM player can detect still markscontained in data stream while decoding data stream recorded in aDVD-ROM disk.

However, a HDVD-player may not have a MPEG decoder as an internalcomponent since it is under development on assumption that it may beconnected a digital television equipped with a MPEG decoder through adigital interface such as IEEE 1394 as aforementioned.

Therefore, even though still marks are inserted in every data streamsection corresponding to still picture in a HD-DVD as in a DVD-ROM, aHDVD player can not conduct still operation if it has not a decoder,that is, it can not detect the still mark.

In addition, a digital television developed at present can not supportstill function for data stream when it receives data stream from a HDVDplayer connected through a digital interface, so that it is urgentlyrequired to develop a method of presenting a specific data streamsection from a disk device such as a HDVD player in a still picture at adigital television.

SUMMARY OF THE INVENTION

In the method of reproducing a still picture from a recording mediumaccording to one embodiment of the present invention, an I-picture and anumber of P-pictures are output as a still picture based on video datareproduced from the recording medium. For example, the P-pictures outputrepresent a same picture as the I-picture being output.

In another embodiment of the present invention, the I-picture and thenumber of P-pictures representing a still picture are received anddecoded for display.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention, illustrate the example embodiments ofthe invention, and together with the description, serve to explain theprinciples of the present invention.

In the drawings:

FIG. 1 shows a digital television and a HDVD player to which a methodfor supporting a still picture of data stream recorded in a diskaccording to the present invention is applied;

FIG. 2 shows a format example of a recorded stream to embody a stillpicture supporting method according to the present invention;

FIG. 3A shows a format example of a recorded stream to embody anotherstill picture supporting method according to the present invention;

FIG. 3B shows an information example written in a cell associated with astream object containing a still picture data; and

FIG. 4 shows a transmission example of a recorded stream correspondingto a still picture according to another embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

In order that the invention may be fully understood, exemplaryembodiments thereof will now be described with reference to theaccompanying drawings.

FIG. 1 shows a digital television 200 and a HDVD player 100 to which amethod for supporting a still picture of data stream recorded in a diskaccording to the present invention is applied. The digital television200 and the HDVD player 100 are connected each other through a IEEE 1394digital interface.

The data written in a HD-DVD which is to be playbacked in the HDVDplayer 100 is grouped into high-density stream objects (called ‘HOBs’hereinafter). A HOB may correspond to a single program or a digitalstream recorded from recording start to stop, and it is to be associatedwith each cell which is used for determining the playback sequence ofmoving picture contents recorded in a HD-DVD.

FIG. 2 shows a format example of a recorded stream to embody a stillpicture supporting method according to the present invention.

As shown in FIG. 2, the data stream belonging to a certain HOB containsa still packet as still information. The function of a still packet isto command the digital television 200 to repeat to decode a streamconstituting a single picture following the still packet instead ofadvancing the reproduction, and a still packet contains still durationinformation indicating how long the requested still operation lasts. Thestill duration is classified into two types of the definite and theindefinite. The definite type may have time value ranging from 1 to 254seconds, and the indefinite type is used in a condition that a keycommand from a user is necessary.

When the data stream recorded as in FIG. 2 is reproduced in the HDVDplayer 100 and is transmitted to the digital television 200 through theisochronous channel of the IEEE 1394 digital bus, the still packet isalso transmitted to the digital television 200 without being decoded.When the digital television 200 receives the still packet while decodingthe received data stream into real video and/or audio signal, itextracts still duration information from the received still packet.After that, the digital television 100 decodes data stream section,which is following the still packet, corresponding to a single pictureand then repeats outputting the just-decoded video picture during thetime indicated by the extracted still duration information.

If the time indicated by the still duration information expires, thedigital television 200 stops repeating of decoding of same picture, andthen resumes to decode next pictures, which may have been already storedin an internal buffering memory, succeeding the still picture.

Through the above-explained operations, a picture can be held as a stillpicture in a digital television for a certain time.

In the above-explained embodiment of the still picture supportingmethod, an additional command for holding a picture and resumingsuccessive decoding needs not be sent from the HDVD player 100 to thedigital television 200.

Instead of positioning a still packet before a still picture, a stillpacket may be preceded by a still picture. In this case, the HDVD player100 may turn its mode into a pause without advancing next pictures assoon as it identifies a packet as a still one based on a packet header.And the digital television 200 repeats decoding a partial data stream,which is received prior to a still packet, constituting a single picturewhen the received packet is determined as a still one. Thisinteroperation between the HDVD player 100 and the digital television200 can also achieve still function.

The still packet may not contain information on still duration. Instead,the HDVD player 100 resumes data reproduction from recorded datafollowing the still packet and transmits the reproduced data stream tothe digital television 100 if a user requests release of still status.According to the resumption of data reproduction, the digital television200 receives data packets next to the still packet, then it acknowledgesthe reception of data packet as release of still picture, and decodesthe received data packets as soon as it stops repetition of decoding ofone picture.

FIG. 3A shows another format example of a recorded stream to embody astill picture supporting method according to the present invention.

As explained above referring to FIG. 2, the data written in a HD-DVDwhich is to be playbacked in the HDVD player 100 is grouped into HOBs. AHOB is also corresponding to a single program or a digital streamrecorded from recording start to stop, and it is related with each cellwhich is used for determining the playback sequence of moving picturecontents recorded in a HD-DVD.

And, a HOB is composed of high-density stream object units (referred‘HOBUs’ hereinafter), and a data stream constituting a HOBU is recordedacross a lot of data packs as shown in FIG. 3A. A data pack is a dataaccessing unit whose size is physically readable and/or writable at atime, that is, it is corresponding to a sector of a DVD-ROM. Each datapack consists of a pack header and several transport packets written init.

The pack header comprises fields of ‘STILL Indicator’, ‘SYS_PCR_base’,‘SYS_PCR_ext, and ‘Reserved’. A transport packet may contain a programclock reference (PCR) which consists of a 9-bit extension value and a33-bit base value according to the MPEG standard. The extension value isa modulo-300 counter that is incremented at a rate of 27 MHz, whereasthe base value is incremented at a rate of 90 KHz. If a transport packetcontains a PCR, the PCR is copied to the fields of 33-bit ‘SYS_PCR_base’and 9-bit ‘SYS_PCR_ext’, respectively. The field of ‘STILL Indicator’ isa 1-bit flag and is used to indicate whether or not a data pack has datastream to be transmitted repeatedly. That is, if the flag is 1, it meansthat the pack and following packs including data of Infra-coded picture(I-picture) and predictive pictures (P-pictures) should be transmittedrepeatedly.

In addition, a cell associated with a HOB containing one or more stillpictures consists of general information and still picture entry pointinformation as shown in FIG. 3B. The general information has variousinformation on reproduction sequence of still pictures, whether there isstill picture or not, and the number of still pictures. And, the stillpicture entry point information has information indicating all of HOBUsin which data stream sections corresponding to still pictures arewritten. The information on whether there is still picture or not andthe number of still pictures is written in 1-byte field of ‘Still_YES’.

Therefore, when reproducing a HD-DVD, the HDVD player 100 examinesinformation written in a cell to know whether there is still picture andwhere still picture is written among a lot of HOBUs, and searches for acorresponding HOBU based on the known information. Then, it examines thesuccessive pack headers belonging to the HOBU to know whether the valueof ‘STILL Indicator’ field is 1 or not.

If the value is 1, the HDVD player 100 reads data stream sectioncontaining I-picture data and next P-picture data only and then repeatsto transmit the read data stream section to the digital television 200as shown in FIG. 4. The I-picture data is composed of a sequence header,a header of group of pictures (GOP), and real video data, and theP-picture data is composed of a header and predictive real data.

The transmission ratio of I-picture to P-picture is 1:15. That is, aI-picture is transmitted once every 15 transmission of P-picture. Whentransmitting the I-picture repeatedly, the HDVD player 100 generates aPCR whose value is transporting time of each transport packetconstituting the I-picture, and inserts it into every packets or every afew packets. When transmitting P-pictures repeatedly, the HDVD player100 transmits P-picture header only without transmitting predictive realdata.

The information of transmitting repetition duration, i.e., stillduration may be written in a cell or a pack header. If this informationhas been written, the HDVD player 100 resumes next reproduction afterstopping the transmitting repetition when the still duration expires, ifhas not, it resumes next reproduction when a user requests to do that.

In this embodiment of still picture supporting method, the digitaltelevision 200 needs not conduct an additional operation for still mode,instead, it just conducts a normal operation to decode the received datastream section provided repeatedly from the HDVD player 100.

The still picture supporting method according to the present inventionmakes it possible to present a background image of menu bars forselection of various functions provided from a HD-DVD and a menu screenfor editing a content scenario of a moving picture program recorded in aHD-DVD as a still picture on a digital television on condition that aHDVD player is delivering real data in the format of data stream to adigital television connected through a digital interface such as IEEE1394.

The invention may be embodied in other specific forms without departingfrom the sprit or essential characteristics thereof. The presentembodiments are therefore to be considered in all respects asillustrative and not restrictive, the scope of the invention beingindicated by the appended claims rather than by the foregoingdescription and all changes which come within the meaning and range ofequivalency of the claims are therefore intended to be embraced therein.

What is claimed is:
 1. A method of retrieving a still picture, themethod comprising: receiving a video data stream and a still indicatorbeing a 1-bit flag; determining whether or not the video data streamincludes the still picture based on the still indicator, the stillindicator being one of a first indicator value indicating that the stillpicture exists in the video data stream and a second indicator valueindicating that the still picture does not exist in the video datastream; and obtaining the video data stream including the still pictureusing identification information if the still indicator is the firstindicator value.
 2. The method of claim 1, further comprising: obtainingthe still picture from the video data stream based on the stillindicator; and decoding the obtained still picture.
 3. The method ofclaim 2, further comprising: presenting the decoded still picture,according to information associated with the still picture.
 4. Themethod of claim 1, wherein the still picture includes at least oneI-picture.
 5. The method of claim 1, wherein the still picture isincluded in at least one still packet having a still packet header, thestill packet header including clock information.
 6. An apparatus forretrieving a still picture, the apparatus comprising: a receiving unitconfigured to receive a video data stream and a still indicator being a1-bit flag; a controller configured to: determine whether or not thevideo data stream includes the still picture based on the stillindicator, the still indicator being one of a first indicator valueindicating that the still picture exists in the video data stream and asecond indicator value indicating that the still picture does not existin the video data stream, and obtain the video data stream including thestill picture using identification information if the still indicator isthe first indicator value.
 7. The apparatus of claim 6, furthercomprising a decoder configured to decode the video data stream.
 8. Theapparatus of claim 7, wherein the controller is further configured toobtain the still picture from the video data stream based on the stillindicator, and to decode the obtained still picture.
 9. The apparatus ofclaim 8, wherein the controller further configured to present thedecoded still picture according to information associated with the stillpicture.
 10. The apparatus of claim 6, wherein the still pictureincludes at least one I-picture.
 11. The apparatus of claim 6, whereinthe still picture is included in at least one still packet having astill packet header, the still packet header including clockinformation.